Compositions for topical application to the skin, whether purely cosmetic, pharmaceutical, or mixtures thereof, heavily rely on the penetrating ability of the composition for maximum efficacy. For example, treatments of fungal infections of the toe nail, or toe nail discoloration due to other underlying factors, are largely dependent on the ability of the active agent, an antifungal to penetrate the skin surrounding the nail as well as the nail itself. In this regard nails are actually produced by living skin cells in the toe or finger.
Additionally certain ingredients used in cosmetic applications can hydrate, thin, and normalize the color of nails and skin. Rehydrating a fungal nail that is dehydrated and dried out can increase porosity of the cells in the nail matrix making it easier for penetration of agents needed to treat the nail, e.g., for fungus.
With particular respect, and by way of example only, for the treatment of nail disorders such onychomycosis or psoriasis affecting the nails, a widely used prescription antifungal is sold under the trademark Jublia®. The composition of the Jublia® antifungal composition, uses a vehicle in which the active ingredient is dissolved, which preferably comprises a linear or branched aliphatic lower alcohol, such as ethanol, methanol, propanol, or isopropanol. U.S. Pat. No. 10,05,444 ('444 patent), incorporated herein by reference for all purposes, covers the Jublia® antifungal composition. The '444 patent encompasses and is focused on the fact that the composition claimed therein meets a significant need for a pharmaceutical composition that provides for enhanced penetration of a pharmaceutical agent contained within the composition into, under, around, and through a nail into the nail bed. To accomplish enhanced penetration, and in addition to the lower alcohol, the composition of the '444 patent also relies on a surfactant to reduce surface tension and a volatile silicone to act as a wetting agent. In any event, the teachings of the '444 patent highlight the fact that penetration is quite important in successfully treating skin disorders, e.g., fungal infections, of the nails and surrounding tissue.